The website incorrectly represents it. Since Lion, how the macOS scrollbar/position looks depends on your input device. By default if you are using a regular m

The website incorrectly represents it. Since Lion, how the macOS scrollbar/position looks depends on your input device. By default if you are using a regular mouse, the scrollbar is displayed with a light-gray marker for the current position (much like the Windows 10 example to the right). If you are using a multi-touch input device (Magic Mouse or Trackpad), the scrollbar is hidden entirely by default. This includes the space or 'track' left for it, the scrollbar just appears as a floating bar when you start scrolling. You can change this via settings to always show track and position.